1. Field of the Invention
This invention relates to molded plastics having improved abrasion resistance based on polyurethanes containing chemically incorporated polysiloxanes, to a process for their production and to their use as shoe soles.
2. Description of the Prior Art
Optionally cellular molded plastics based on polyurethanes and having a solid surface and their preparation are known (cf., for example, U.S. Pat. No. 4,065,410, U.S. Pat. No. 4,218,543, U.S. Pat. No. 3,726,952, British Pat. 1,365,215, U.S. Pat. No. 4,033,912, U.S. Pat. No. 4,024,090, U.S. Pat. No. 4,058,492, U.S. Pat. No. 4,098,731, EPA 17,928, EPA 44,481, EPA 69,286 and DE-OS 3,133,859). In this regard, "molded polyurethane" plastics include not only pure polyurethane plastics obtained by reacting organic polyisocyanates with organic polyhydroxyl compounds, but also plastics prepared by trimerizing a portion of the isocyanate groups to form isocyanurate groups and/or by reacting a portion of the isocyanate groups with co-reactants containing amino groups to form urea groups. These molded polyurethane plastics can be produced in soft, semi-hard and hard form. In particular, the elastomeric, optionally cellular "semi-hard" moldings based on polyurethanes have been used for many years, inter alia, for the production of shoe soles. A disadvantage of these plastics, particularly those based on polyether polyols, is the very high wear. Thus, there is a demand to provide optionally cellular molded polyurethane plastics with a solid outer skin, in particular a semi-hard elastomer, which are useful as shoe soles and do not have the disadvantage mentioned.
Accordingly, an object of the present invention was to develop new polyurethane moldings which satisfy the demand for reduced wear without having an adverse affect on the other desirable properties.
This object has been achieved in accordance with the polyurethane moldings according to the invention as described hereinafter.